﻿using System;

class HexadecimalAsBinary
{
    static void Main()
    {
        string binaryNumber = "1e0f3";
        int tempNumber = 0;

        for (int i = 0; i < binaryNumber.Length; i++)
        {
            string str = binaryNumber[binaryNumber.Length - 1 - i].ToString().ToLower();
            switch (str)
            {
                case "a":
                    str = "10";
                    break;
                case "b":
                    str = "11";
                    break;
                case "c":
                    str = "12";
                    break;
                case "d":
                    str = "13";
                    break;
                case "e":
                    str = "14";
                    break;
                case "f":
                    str = "15";
                    break;                    
            }

            int letter = int.Parse(str);
            tempNumber += letter * (int)Math.Pow(16, i);
        }
        string result = "";
        while (tempNumber != 0)
        {
            result += (tempNumber % 2).ToString();
            tempNumber /= 2;
        }
        char[] reversedArray = result.ToCharArray();
        Array.Reverse(reversedArray);
        result = new string(reversedArray);
        Console.WriteLine(result);
    }
}
